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Flashcards in UWorld-Cardiology Deck (33)
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1

what drug would you use to treat beta blocker overdose and why

glucagon; it activates GPCRs in cardiac myocytes leading to increased adenylyl cyclase activity --> increased cAMP leading to increased contractility and heart rate in cardiac myocytes

2

tetralogy of Fallot, transposition of the great vessels and truncus arteriosus all result from what impaired process during embryologic development

migration of the neural crest cells into the truncus arteriosus and bulbus cordis in preparation to grow in spiraling fashion and separate the aorta from the pulmonary artery

3

which artery usually supplies the diaphragmatic surface of the heart

the right coronary artery (b/c it usually supplies the PDA and the PDA supplies the inferior left ventricle, which lies against the diaphragm)

4

name the four features of Tetralogy of Fallot

pulmonic stenosis, RVH, overriding aorta, and VSD

5

how long after onset of total ischemia does cardiac myocyte contraction cease

less then 60 seconds

6

explain the mechanism of action by which NO causes relaxation of smooth muscle

NO activates guanylate cyclase leading to increased cGMP, cGMP downregulates intracellular calcium, which decreases myosin light chain kinase activity leading to myosin dephosphorylation and consequent relaxation of smooth muscle

7

what is the equation for the maintenance dose

maintenance dose= (steady state plasma conc.) X (clearance) / (bioavailability)

8

which cardiac disease is characterized by an opening snap followed by a low-pitched late diastolic rumble

mitral stenosis (opening snap= abrupt halting of mitral valve leaflets due to fusion of the valve tips)

9

which cardiac disease is characterized by a mid-systolic click followed by a crescendo murmur

mitral valve prolapse
(mid-systolic click= sudden tensing of chordae tendinae)

10

which anti-arrhythmic drug used to treat ventricular tachycardia is most selective for ischemic myocardium over normal cardiac tissue

lidocaine suppresses rapidly depolarizing and depolarized cells (though it is being replaced by amiodarone for management of v. tach)

11

explain pulsus paradoxus, what it is and when you would see it

pulsus paradoxus is a decrease in SBP during inhalation that is greater than 10mmHg; this occurs in disease that impair right heart expansion into the paricardial space; the right ventricle must instead push the interventricular septum into the left ventricular side decreasing EDV and thereby decreasing SBP

12

what does an S3 indicate

left ventricular failure or increased left end systolic volume

13

what is milrinone and what effect does it have in the heart vs. vascular smooth muscle

milrinone is a phosphodiesterase isoenzyme 3 inhibitor;
it increases cAMP to increase contractility in the heart and vasodilation in vascular smooth muscle

14

what is the main way that nitrates work to treat angina pectoris

nitrates decrease preload (thereby lowering ventricular work and O2 demand)

15

which of these three tissues have beta-1 receptors:
cardiac muscle
vascular smooth muscle
juxtaglomerular cells

beta-1 receptors are found in cardiac muscle, juxtaglomerular cells and vascular smooth muscle

16

what keeps a patent ductus arteriosus open?
what closes a patent ductus arteriosus?

prostaglandins keep a PDA open
indomethacin or NSAIDS close a PDA

17

what is amyl nitrite and why isn't it used anymore

a volatile inhalant historically used to treat angina pectoris;
discontinued because of side effects of cutaneous flushing and postural hypotension

18

bounding femoral and carotid pulses with head bobbing indicates what cardiac abnormality

aortic regurgitation
(note: head bobbing due to bounding carotid pulse= de Musset's sign

19

what are the resting potentials for cardiac vs. skeletal myocytes

cardiac myocytes: -90mV
skeletal myocytes: -75mV

20

which bacteria synthesize dextrans from glucose

strep viridans bacteria;
this enables them to colonize enamel and valves

21

what reaction is catalyzed by endothelial nitric oxide synthase (eNOS)

in response to ACh, bradykinin or shear stress, intracellular calcium increases triggering eNOS to catalyze this reaction:
Argining + O2 ----> NO + citrulline

22

what is the commonest cause and location of aortic rupture

motor vehicle accident;
aortic isthmus: the connection between the ascending and descending, just distal to the branch point of the left subclavian arterty

23

what group of drugs and what particular drug from that class has been proven to slow progression and lower mortality for CHF

beta blockers; particularly carvedilol

24

what is seen under the microscope for cardiac tissue 3 hours after myocardial infarction

trick question! minimal change is detectable before 4 hours

25

what is Trousseau's syndrome

migratory thrombophlebitis due to hypercoagulability (often seen in patients with disseminated cancers)

26

list the ventricular muscle, atrial muscle, AV node and Purkinje system in order from fastest to slowest in terms of action potential velocity

Purkinje system is fastest (2.2 m/sec), then the atrial muscle (1.1 m/sec), then ventricular muscle (0.3 m/sec), and the AV node is slowest (0.05 m/sec)

27

which drug for MRSA has a side effect of myopathy and increased Cr kinase;
how does it work?

daptomycin can cause myopathy and increased creatinine kinase;
it works by depolarizing the bacterial cellular membrane

28

best indicator of severity of mitral regurgitation =?

audible S3 (suggests high volume of regurgitant flow into LV)

29

name the proteins associated with the following types of amyloidosis:
-localized cardiac atria (isolated atrial amyloidosis)
-localized thyroid gland
-localized pancreatic
-localized pituitary gland
-Alzheimer's and Cerebral Amyloid Angiopathy
-systemic amyloidosis

-cardiac atria: atrial natriuretic peptide
-thyroid gland: calcitonin
-pancreatic: amylin
-pituitary gland: prolactin
-Alzheimer's and CAA: beta-amyloid
-systemic amyloidosis: immune globulin light chain

30

in the lung, a cavitary lesion with an air-fluid level =?

lung abscess (most common cause is aspiration => abscess with normal mouth flora)